Conventional piston dampers include MR dampers having a cylinder containing an MR fluid and having an MR piston which slideably engages the cylinder. The MR fluid passes through an orifice/slot of the MR piston. Exposing the MR fluid in the orifice/slot to a varying magnetic field, generated by having a controller provide a varying electric current to a coil of the MR damper (i.e., an electric coil of the MR piston), varies the damping effect of the MR fluid in the orifice/slot providing variably-controlled damping of relative motion between the MR piston and the cylinder. The electric current is varied to accommodate varying operating conditions, as is known to those skilled in the art. A rod has a first end attached to the MR piston and a second end extending outside the cylinder and attached to one of a vehicle frame and a vehicle suspension system component. The cylinder is attached to the other of the vehicle frame and the vehicle suspension system component. The MR damper dampens relative motion of the vehicle frame and the vehicle suspension system component along the direction of piston travel. However, the viscosity (damping effect) of the MR fluid varies with the temperature of the MR fluid. If the temperature of the MR fluid (which can be considered to be the temperature of the coil of the MR damper) could be calculated, then the varying damping effect with temperature of the MR fluid could be compensated for in the electric current provided to the coil by the controller, as is within the level of skill of the artisan.
What is needed is a method for determining the coil temperature of an MR damper of an operating automotive vehicle.